Excavation machines can be used to efficiently move large amounts of material. During movement of the material, it can be important to keep track of the amount of material moved. For example, the amount of material moved during each excavation cycle can be used in determining productivity of the excavation process or of a particular machine or operator. In another example, the material amount can aid in determining completion of a project, billing of a particular customer, and/or scheduling of the excavation machines.
The amount of material moved by an excavation machine can be determined in many different ways. For example, a loading machine can be equipped with a pressure sensor that monitors pressures in a lifting arm of the machine, the pressures then being related to the amount of material dumped into a waiting haul vehicle. In another example, a haul machine could be equipped with a strain gauge associated with a strut of the machine, a measured deflection or deformation of the strut then being related to the amount of material deposited inside the haul machine. In yet another example, the haul machine may be driven onto a scale that measures a total weight of the machine and load, the empty weight of the haul machine then being subtracted from the total weight to determine the amount of material in the machine. In a final example, the amount of material in the loading or haul machine may be calculated based on an estimated volume of the material (e.g., based on a known volume of a full work tool associated with the machine or based on a scanned volume inside the work tool) and an estimated density of the material. Unfortunately, each of these different ways of determining the amount of material being moved may produce different results and/or require different time and resources. And because multiple different systems and processes may be used at the same worksite, accuracy and consistency can be difficult to attain.
One attempt to improve payload monitoring is disclosed in U.S. Pat. No. 8,626,541 of Doan et al. that issued on Jan. 7, 2014 (“the '541 patent”). Specifically, the '541 patent discloses a system for dynamically recalibrating a payload monitoring system located onboard a loader. The system includes a scale, over which a haul machine previously filled with material by the loader travels before leaving a quarry. A measurement made by the scale is compared to a load measurement made by the payload monitoring system to create a positive or negative delta value. The delta value is compared to a threshold and, when the delta value is higher than the threshold, the payload monitoring system is recalibrated by adjusting a tare weight reading of an empty loader bucket by the delta value.
While the system of the '541 patent may have improved accuracy and consistency in some situations, it may still be less than optimal. Specifically, the system may lack broad applicability to machines other than loaders. In addition, the system may not be available at worksites that are not equipped with a scale.
The disclosed system is directed toward overcoming one or more of the problems set forth above and/or other problems of the prior art